Sweet and sour steak

Start by preparing the sweet and sour sauce. In a small bowl, mix the tomato ketchup, white vinegar, brown sugar, soy sauce, and water. Stir until the sugar is dissolved.
In a separate small bowl, dissolve the cornstarch in a tablespoon of cold water to create a cornstarch slurry.
Heat a pan or skillet over medium-high heat. Add the vegetable oil.
Season the beef steak with salt and black pepper on both sides.
Place the steak in the hot pan and cook to your desired level of doneness. For medium-rare, cook for about 3-4 minutes per side. Adjust the cooking time based on your preference.
Remove the steak from the pan and let it rest for a few minutes. Then, slice it into thin strips.
In the same pan, add the diced onion and bell peppers. Sauté them for 2-3 minutes until they start to soften.
Add the sweet and sour sauce mixture to the pan and stir well.
Pour in the cornstarch slurry while stirring continuously. This will thicken the sauce.
Add the pineapple chunks and sliced steak to the sauce. Cook for an additional 2-3 minutes, allowing everything to heat through and the flavors to meld.
Taste the sauce and adjust the seasoning if needed. You can add more sugar for sweetness or more vinegar for tanginess, according to your preference.
Serve the sweet and sour steak hot, garnished with some sliced spring onions or sesame seeds, if desired.
Enjoy your homemade sweet and sour steak!